Tag: identifying sugar maples

Many maple trees live in the forests that line the valley and bluff of the Illinois River. The vast majority of these maples are native sugar maples (Acer saccharum), also called Rock Maple or Hard Maple. The Norway maple (Acer platanoides) is making definite inroads in areas. Until about 100 years ago the majority of trees in these same forests were oak and hickory trees with a minority of Sugar maples. Since then with the lack of forest fires, the maple, basswood, buckeye and other fire intolerant but shade tolerant trees began to dominate the tree population.

Non-native Norway maple was introduced from Europe around 1750 as a landscape tree. Norway maple tolerates shade, transplants easily, tolerates soil types from clay to sand, tolerates pH from acid to alkaline, and grows better in hot, dry conditions than does Sugar maple. Norway maple trees escaped from landscaped areas and are now crowding out native fauna in some areas. Concern is growing that the number of oak and hickory trees will continue to diminish in the forest areas dominated by shade loving plants where less than fifty percent of sunlight reaches the forest floor. Oak acorns need more sunlight to germinate and grow to effectively compete with maple offspring which grow quite well in the shade.

While hiking in the woods, I find it challenging to differentiate Sugar from Norway maples and thus determine the status of the local Norway maple invasion. Both of these maple species have simple leaves located opposite each other on the stem and have opposite branches. During the growing season, Norway maple leaves are unique in that a milky fluid is seen when their petiole is removed from the stem.

Norway maple leaf

The Norway maple leaves have a fuller, sub-chordate base, 5-lobes, each with a sharp point, and additional sharp points occur along the lobes. From September to October the maple’s fruiting body, the samara, translocates by whirling in the breeze on its way to the ground.

Sugar maple with sharp points at the apex of each of five lobes while other areas have blunt pointsSugar Maple’s Horseshoe shaped samara

These samara of the Norway and Sugar maples are distinctly different. Sugar maple samara have a shape somewhat similar to a horseshoe while the Norway maple’s samara is more horizontal and looks more like the shape of a wooden coathanger.

Note the conically pointed sugar maple terminal bud

The terminal bud of the Norway maple is rounded and 1/4 to 3/8 inch while the terminal bud of the Sugar maple is smaller, 3/16 to 1/4 inch , and has a pointed and conical shape. In the fall the Norway maple is one of the last trees to loose its yellow leaves. This feature makes it easiest to identify and differentiate these two maple trees in the fall.

For more information on Maple buds and bark see: http://blogs.pjstar.com/gardening/2014/01/31/winter-identification-of-norway-maple-and-sugar-maple/